Wood grinder regulating device



Aug. 30, 1932. v. RUsTERHoLz WOOD GRINDER REGULATING DEVICE Filed Dec. l1, 1928 2 Sheets-heei 1 Fig. 1.

Inventor Viktor Rusterholz By l* Alforney Aug. 30, 1932.. A v. Rus'rERHoLz 1,873,932

WOOD GRINDER REGULATING DEVICE Filed Dec. 11, 1928 2 Sheets-Sheet 2 Invenfor Viktor' Rusferholz Attorney Patented Aug. 30, 1932 UNITEDv STATES PATENT OFFICE VIKTOR RUSTERHOLZ, OF ZURICH, SWITZERLAND, ASSIGNOR TO AKTIENGESELLSCHAFT BROWN BOVERI & CIE., OF BADEN, SWITZERLAND, A JOINT-STOCK COMPANY OF SWITZERLAND WOOD GRINDER REGULATING DEVICE Application led December 11, 1928, Serial No. 325,241, and. in- Germany December 16, 1927.

10 operates mechanically and the generator acts electrically on the load-regulating device. Here'tofore, electrical regulation of both components acting on a load-maintaining or regulating device has been used only for 15 electrically driven devices of the above char act-er rather than for such mechanically driven devices.

It is, therefore, among the objects of the present invention to operate the load-main* taining, regulating device of a wood grinder in electrical dependence on both the speed of the prime mover and of a generator connected therewith.

Another obje'ctof the invention is to regu ulate the load on a mechanically operated wood rinder entirely by electrical regulation ependent on the loperation of the grinder-driving device.

Other objects and advantages will be apparent from the description of the accom panying drawin in which:

Figure 1 is a iagrammatic representation of a wood grinder control system embodying the present invention; and

Fig. 2 is a modified embodiment of the present invention.

In the drawings, a wood grinder 5 is directly connected to be driven by a turbine or similar prime mover 6, which prime mover also drives a synchronous enerator 7 on the same shaft with the grin er 5.

A voltage transformer 8 and a current transformer 10 are connected to the output circuit of the generator 7 and toa potential regulator 11 which controls the current in a circuit including a constant voltage line 16 and an excitationl winding 12 of an auxiliary dynamo 13. A second excitation winding 15 for the auxiliary dynamo 13 is also supplied from constant. voltage line 16 and is `controlled by a variable ohmic resistance 17 in dependence on the speed of operation of turbine 6. The usual turbine regulator is mechanically connected, by any well-known means, to the movable contact of the resistance 17 and operates to vary the resistance in accordance with variations in the position of the regulating device of the turbine. The varmature of dynamo 13 is connected in circuit with a variable resistance 18 and with the actuating coils of a quick-acting regulator 20 and is adapted, by its movement, responsive to variations of current in the dynamo 13 to regulate the current in the field winding of a dynamo 22 which supplies current to a driving motor 23 for the feeding, or loading, device of the grinder (not shown).

In operation of the embodiment shown in F ig. 1, let it be assumed that the load on grinder 5 and that on generator 7 changes either positively vor negatively. Then the load on turbine 6 will change in direct ratio with the change in the total load on the two machines, grinder 5 and generator 7. Change in the total load of the two said machines, constituting the load on turbine 6, is accompanied by a change in the current in field winding 15 of auxiliary dynamo 13, by reason ofthe change in resistance 17 controlled in accordance with the speed of turbine 6. Change in the load on generator 7 alone is accompanied by a change in the current in field winding 12 of auxiliary dynamo 13, the current in winding 12 being controlled through regulator 11 in accordance with the load on generator 7. The field windings 15 and 12 are. so connected that the resultant excitation of dynamo 13 'changes as the algebraic difference between the changes in the fields 15 and 12, respectively; that is, as the algebraic vdifference between thefchange in a function of turbine speed and the change in the generator load. This diierence, it will be noted, represents the change in the load on grinder 5 alone. The change in the resultant field of dynamo 13 is accompanied by a corresponding change in the current in field 21 of dynamo 22. The latter field current is controlled by regulator 20 which is actuated by dynamo 13, said dynamo 13 and regulator 20 being so connected that the current in field winding 21 changes inversely as the algebraic difference between the change in a function of turbine speed (controlling field 15 of dynamo 13) andthe change inthe generator load (controlling field 12 of dynamo 13). Therefore, grinder feed motor 23, supplied by dynamo 22, changes the load on grinder 5 inversely as the original change in said grinder load and thereby brings said load back to normal.

As an example, assume that the load on generator 7 increases and simultaneously the load on grinder 5 decreases. Then the load on turbine, 1 changes by an amount equal to the. algebraic sum of the changes of load in the l two driven machines. Field 15 changes in accordance with the change in the speed of turbine 6; eld 12 changes only in accordance with the change of load on generator 7. Thev resultant field of dynamo 13changes in accordance with the algebraic difference between the change ina function of turbine speed and the change in the generator load; that is, in -acordance with the decrease in the grinder load. Dynamo 13, through regulator l 20, acts to increase the current in eld 21 of dynamo 22. The current supplied by dynamo 22 to grinder feed motor 23 is, therefore, increased and the load on grinder 5 thereby increased to normal.

Adjustment of the normal grinder load,

-which is to be kept constant after initial adjustment, to different values, is effected by regulating the resistance 18, thereby controlling the current of dynamo 13. Change in the value ofthe resistance in series with dynamo 13 is accompanied by a corresponding change inthe current in eld winding 21 and, therefore, in the normal load on grinder 5.

A further embodiment of the invention is shown in Fig. 2, in which the load on a enerator, as three-wire generator 28, driven by a prime mover (not shown? is kept constant by adjustment of the loa on the motor of va grinding device supplied therefrom.

Frequently, such generators are connected to motors driving 'paper making :machines in whichl the several portions must run at a predetermined speed andconsequently the load must be regulated-at constant voltageby keeping the current load constant. The current supplied to the re lator 20 is kept constant by an auxiliary ylnamo 13 excited by two windings 30, 31, each one of which is connected by means of a shunt as 32, 33, to one of the line wires of the generator system. The voltage of the dynamo 22 is controlled by a quick-acting voltage regulator 20 as abovedescribed, yand is, therefore; a measure of the load on generator 28. The operation o f the system shown in Fig. 3

will he obvious b reference to th'edescriptionof the operation of Fig. 1. In Fig. 3 the asvaoss resultant field of dynamo 13 is a function of the load on generator 28. The arrangement of parts is such that the load on gr1nd-` erA 5, controlled by feed motor 23, varies inversely as the load on generator 28.

The generator output may be regulated by varying resistance 18 in series with the voltage coil of the regulator. Change in the resistance 18 is accompanied by a corresponding change in the load on grinder 5,

as hereinbefore explained and the generator made .in the arrangement and character of the elements without departing from thespirit thereof or from the scope of the appended claims.

The invention claimed is:

1. In a system for automatic regulation of a motor, a generator, an auxiliary dynamo, means connected with said generator for controlling said dynamo, a second d amo, means for controlling said second. ynamo connected with said auxiliary dynamo, and a motor connected with the second dynamo and operated thereby.

2. In a system for automatic-regulation of a motor, a. prime mover, a generator operated by said prime mover, an auxiliary dynamo having excitation windings, means'connected with the output circuit of said generator for exciting one of said dynamo windings, a constant voltage supply line for exciting another of said windings, a second dynamo, means connected with said auxiliary dynamo for controlling excitation of said second dynamo, and a motor-actuated by said second dynamo. l

3. Ina system for automatic regulationl of a motor, a prime mover, a generator operated by said prime mover, an auxiliary dynamo having excitation windings therefor, a constant voltage line for exciting one of the v windings, means electricall connected with the output circuit of sai generator andd with said constant voltage line :for exciting vanother of the windings, a second dynamo havin -a'n excitation winding, means con.- necte with said auxiliary dynamo and with the excitation winding of said second dynamo for controlling the latter, and a motor 'operated by said second dynamo.

4. In a system for automatic regulation of a motor, a prime mover having regulating means therefor, including a generator operi ated by said prime mover, transformers in the output circuit of said generator, a regulator connected .with said transformers, a const ant voltage line connected to said regulator, an auxiliar dynamo having excitationwindings, one o the windings being controlled b Asaid regulator, a resistance in circuit wi another of the excitation windings connected to said constant voltage line, said resistance being regulated by said prime mover regulating means, a.Y second dynamo, controlled by said auxiliary dynamo, regulating means electrically connected with said dynamos, and a motor connected with said second dynamo and controlled thereby.

5. In a system for automatic regulation m of a motor, a prime mover having regulating means connected therewith, including a generator operated by said prime mover, a voltage transformer connected to the output circuit of said generator, a current transformer connected with the output circuit of said generator, a regulator connected with said transformers, a constant voltage line, said regulator being connected with said line, an auxiliary dynamo having excitation windings, one

of the widings being controlled by said regulator, a resistance in circuit with another of the excitation windings supplied from said constant voltage line, said resistance being variable in dependence on the regulating means of said prime mover, a second dynamo having an excitation winding, regulating means connected with said auxiliary dynamo and with said constant voltage line vfor controlling excitation of said second dynamo winding, and a motor operated by said second dynamo.

- 6. In a device of the character described, a prime mover, a machine operated by said prime mover, a generator operated by said prime mover, a motor for maintaining a con stant speed of said machine, dynamos controlled in dependence on the operation of said rime mover and said generator, and means or controlling said motor by the action of said dynamos.

4c 7. In a device of the character described, a prime mover, a machine operated by said prime mover, a generator operated by said prime mover, a motor for maintaining a constant speed of said machine, dynamos electrically controlled by the operation of said prime 'mover and said generator, and means for controlling operation of said dynamos by voltages dependent on the output of said generator and on the load of said machine.

8. In a power system comprising a prime mover, an electric generator operated by said prime mover, a machine operated by said prime mover, and means electrically responsive to operation of said prime mover and operation of the saidV generator for automatically regulating the load on said machine, said means comprising an auxiliary dynamo having one field winding excited: by a voltage in function of the speed of said prime mover and 0 having a second winding excited by a voltage in function of the load on said generator.

In testimony whereof I have hereunto subscribed my name this 27th day of November A. D. 1928. 55 v VIKTOR RUSTERHOLZ. 

